diff --git a/core/lib/Drupal/Core/Field/WidgetBase.php b/core/lib/Drupal/Core/Field/WidgetBase.php
index a5549e6701..2ee3127a5a 100644
--- a/core/lib/Drupal/Core/Field/WidgetBase.php
+++ b/core/lib/Drupal/Core/Field/WidgetBase.php
@@ -262,7 +262,7 @@ protected function formMultipleElements(FieldItemListInterface $items, array &$f
           '#type' => 'submit',
           '#name' => strtr($id_prefix, '-', '_') . '_add_more',
           '#value' => t('Add another item'),
-          '#attributes' => ['class' => ['field-add-more-submit']],
+          '#attributes' => ['class' => ['field-add-more-submit', 'button--small']],
           '#limit_validation_errors' => [array_merge($parents, [$field_name])],
           '#submit' => [[static::class, 'addMoreSubmit']],
           '#ajax' => [
diff --git a/core/themes/claro/claro.theme b/core/themes/claro/claro.theme
index d7c49a793e..f5e50e631c 100644
--- a/core/themes/claro/claro.theme
+++ b/core/themes/claro/claro.theme
@@ -941,11 +941,6 @@ function claro_preprocess_field_multiple_value_form(&$variables) {
         }
       }
     }
-
-    // Make add-more button smaller.
-    if (!empty($variables['button'])) {
-      $variables['button']['#attributes']['class'][] = 'button--small';
-    }
   }
 }